Class: SlenderT

Inherits:
Object
  • Object
show all
Defined in:
lib/slender_t.rb

Constant Summary collapse

FCSV = 
CSV

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(contents = nil, opts = {}) ⇒ SlenderT

Returns a new instance of SlenderT.



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# File 'lib/slender_t.rb', line 20

def initialize(contents=nil, opts={})
  @spo, @pos, @osp = {}, {}, {}
  self.load(contents, opts) if contents
end

Instance Attribute Details

#osp ⇒ Object (readonly)

Returns the value of attribute osp.



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# File 'lib/slender_t.rb', line 18

def osp
  @osp
end

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/slender_t.rb', line 18

def pos
  @pos
end

#spo ⇒ Object (readonly)

Returns the value of attribute spo.



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# File 'lib/slender_t.rb', line 18

def spo
  @spo
end

Class Method Details

.load(source, opts = {}) ⇒ Object 



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# File 'lib/slender_t.rb', line 13

def load(source, opts={})
  SlenderT.new(source, opts)
end

Instance Method Details

#add(subject, predicate, object) ⇒ Object 



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# File 'lib/slender_t.rb', line 42

def add(subject, predicate, object)
  add_to_index(self.spo, subject, predicate, object)
  add_to_index(self.pos, predicate, object, subject)
  add_to_index(self.osp, object, subject, predicate)
  [subject, predicate, object]
end

#find(subject = nil, predicate = nil, object = nil) ⇒ Object Also known as: triples 



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# File 'lib/slender_t.rb', line 60

def find(subject=nil, predicate=nil, object=nil)
  begin
    if subject and predicate and object
      if self.spo[subject] and self.spo[subject][predicate] and self.spo[subject][predicate].include?(object)
        return [[subject, predicate, object]]
      else
        return []
      end
    elsif subject and predicate and object.nil?
      return self.spo[subject][predicate].map {|o| [subject, predicate, o]}
    elsif subject and predicate.nil? and object
      return self.osp[object][subject].map {|p| [subject, p, object]}
    elsif subject and predicate.nil? and object.nil?
      return self.spo[subject].inject([]) do |list, h|
        p, objects = h.first, h.last
        objects.each {|o| list << [subject, p, o]}
        list
      end
    elsif subject.nil? and predicate and object
      return self.pos[predicate][object].map {|s| [s, predicate, object]}
    elsif subject.nil? and predicate and object.nil?
      return self.pos[predicate].inject([]) do |list, h|
        o, subjects = h.first, h.last
        subjects.each {|s| list << [s, predicate, o]}
        list
      end
    elsif subject.nil? and predicate.nil? and object
      self.osp[object].inject([]) do |list, h|
        s, predicates = h.first, h.last
        predicates.each {|p| list << [s, p, object]}
        list
      end
    elsif subject.nil? and predicate.nil? and object.nil?
      list = []
      self.spo.each do |s, predicates|
        predicates.each do |p, objects|
          objects.each {|o| list << [s, p, o]}
        end
      end
      list
    end
  rescue
    []
  end
end

#inspect ⇒ Object 



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# File 'lib/slender_t.rb', line 107

def inspect
  self.spo.keys.size > 20 ? "#{self.class}: #{self.spo.keys.size} unique subjects" : "#{self.class}: #{self.spo.keys.inspect}"
end

#load(contents, opts = {}) ⇒ Object

Expects CSV, a filename, or a URL with triples in it If there is a header in the file, use load(contents, :header => true) so that we can ignore the first line If there are special converters needed for FasterCSV to work, include them in the options as well.



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# File 'lib/slender_t.rb', line 30

def load(contents, opts={})
  table = infer_csv_contents(contents, opts)
  return nil unless contents
  table.each do |row|
    self.add(*row)
  end
end

#query(*triples) ⇒ Object

Take a list of triples with variables in them, and resolve the constraints of the triples. Usage: query([ [‘?company’, ‘headquarters’, ‘New York’], [‘?company’, ‘industry’, ‘Investment Banking’], ])



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# File 'lib/slender_t.rb', line 129

def query(*triples)
  bindings = nil
  triples.each do |triple|
    binding_position = {}
    query = []
    triple.each_with_index do |e, i|
      if query_variable?(e)
        binding_position[e] = i
        query << nil
      else
        query << e 
      end
    end
    rows = find(*query)
    if bindings.nil?
      bindings = rows.inject([]) do |list, row|
        binding = {}
        binding_position.each do |var, pos|
          binding[var] = row[pos]
        end
        list << binding
      end
    else
      new_binding = []
      bindings.each do |binding|
        rows.each do |row|
          valid_match = true
          temp_binding = binding.dup
          binding_position.each do |var, pos|
            if temp_binding.include?(var)
              valid_match = false if temp_binding[var] != row[pos]
            else
              temp_binding[var] = row[pos]
            end
          end
          new_binding << temp_binding if valid_match
        end
      end
      bindings = new_binding.dup
    end
    bindings
  end
  return bindings
end

#remove(subject, predicate, object) ⇒ Object 



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# File 'lib/slender_t.rb', line 49

def remove(subject, predicate, object)
  triples = find(subject, predicate, object)
  return true unless triples
  for s, p, o in triples do
    self.remove_from_index(self.spo, s, p, o)
    self.remove_from_index(self.pos, p, o, s)
    self.remove_from_index(self.osp, o, s, p)
  end
  [subject, predicate, object]
end

#save(filename) ⇒ Object 



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# File 'lib/slender_t.rb', line 38

def save(filename)
  File.open(filename, 'wb') {|f| f.write self.to_csv}
end

#to_csv ⇒ Object

Just very basic for now



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# File 'lib/slender_t.rb', line 112

def to_csv
  self.find.map {|row| row.join(',')}.join("\n")
end

#value(subject = nil, predicate = nil, object = nil) ⇒ Object 



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# File 'lib/slender_t.rb', line 116

def value(subject=nil, predicate=nil, object=nil)
  s, p, o = find(subject, predicate, object).first
  return s unless subject
  return p unless predicate
  return o unless object
  nil
end